<!DOCTYPE html>
<html lang="zh-cn">
<head>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <title>Rule</title>
    <style>
        h2 {
            color: gray;
        }

        h2 {
            color: silver;
        }
    </style>
</head>
<body>

</body>
</html>